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What Is a Relational Database Management System?

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  • Written By: Page Coleman
  • Edited By: Allegra J. Lingo
  • Last Modified Date: 06 April 2014
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A relational database management system (RDBMS) is a specific type of database that contain tables of data. These types of databases are often used in supporting either a single or several affiliated software applications. Specific database programming language is used to modify and report on the data. Several techniques can speed data retrieval and reduce duplication.

Organizations may use RDBMS for storing inventory, employee, customer, and other data. Users can interact with the system through software applications that include programming code to work with the database. These software applications can be traditional or web-based.

A relational database management system consists of tables with columns and rows. The column label identifies the data in the rows within the column. Each row contains the actual data for an instance of an entity, which can be a person, location, object, or idea. A customer database, for example, may have columns for the customer's ID, first name, last name, and email address, and each row contains an individual customer’s data.

These systems are accessed and updated using structured query language (SQL). To work with the data, a database developer will write programming statements called queries. Different brands of database management systems may require the use of different versions of SQL, though they have many similarities.

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An RDBMS may use several types of tables. Base tables hold the entire set of data. Temporary tables store data that is being manipulated as a query is running. Results tables store the query outcomes.

Relational database management systems use several types of keys for retrieving data. A primary key identifies one particular instance of an entity. For an employee table, the primary key may be an employee identification number that each employee is permanently assigned to and which no other employee will use. Unique keys are other data elements that are also exclusive to each instance of an entity. For example, a retailer may assign inventory items with unique supplier item numbers.

A third type of key is a foreign key. In the relational model, it establishes relationships between entities. Using foreign keys, a relationship between a company’s customers and each customer's sales can be maintained without duplicating data in the relational database management system.

The speed of data retrieval is important, especially as the amount of data increases. A developer may add an index to an RDBMS to allow queries to run faster. The index typically uses a primary key, such as a tax identification number.

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Discuss this Article

SkyWhisperer
Post 4

@allenJo - I prefer to use database services delivered over the web. Actually I think this is the trend, even for in house applications.

Our company uses a web page to give users access to the database on our server. The advantage of the web page is that there are fewer buttons to push and it allows many people access to the database at the same time.

I suppose you could do that with a traditional application but I think it’s harder.

allenJo
Post 3

@nony - A simple comparison of relational database management systems reveals that they are all very similar, to me at least.

I am not a database guru but I am an analyst. At work we’ve gone through Oracle, Sybase and SQL Server. The article is correct when it says that the SQL is very similar for most of them. There are a few tweaks here or there but they are nearly the same.

What this means for you is that once you learn one database management system, you can learn them all. As a matter of fact, a company looking for a SQL Server developer could conceivably hire you if all you know is Oracle.

That’s because they know you’ll make the transition quickly. I wouldn’t say the same for Access, however. It lives in its own world because it’s more of a desktop application, not an enterprise application.

nony
Post 2

@David09 - Just remember to have a primary key where needed in your data. I’ve worked in companies where the data was all kinds of messed up. Their data didn’t have primary keys and there were duplicate rows.

You have a data integrity mess on your hands, and you have to do a lot of clean up of the data before you can get to the place where you can run queries and stuff like that.

While you’re at it, apply an index – at least one – to your tables as well. An index works the same way as an index in a book. It’s a fast way for the database to find the information without having to go through each record (or through each page, to stay with the book analogy).

David09
Post 1

Database management solutions range from the simple to the complex. I first got started learning Microsoft Access. While not an industrial strength database in any sense of the term, it was more than enough for my needs.

I was able to learn how to design tables to hold data and write queries. Since I was a beginner I used what is known as a query grid to design my queries in a visual manner.

It was easy to link tables and then apply the filters. After that I learned to write the SQL. That was not so easy, but one thing that helped was going online and studying other people’s SQL statements.

Eventually I got the hang of it and it was second nature. I recommend that you start learning with a starter database management system like Access or something else if you really want to learn how to work with relational database management systems.

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